N-Nitroso Perindopril: Chemical Structure, Characterization, and Analytical Significance

Nitrosamine impurities have become an important area of investigation in pharmaceutical quality control because of their potential presence in active pharmaceutical ingredients (APIs), intermediates, and finished drug products. Their identification, characterization, and control are essential parts of pharmaceutical impurity assessment and manufacturing quality management. Among the compounds of interest in this area is N-Nitroso Perindopril, a nitrosamine-related impurity associated with the pharmaceutical compound perindopril.

Perindopril is an angiotensin-converting enzyme (ACE) inhibitor used in the management of hypertension and certain cardiovascular conditions. Its chemical structure contains a nitrogen-containing functional group that makes understanding its potential nitrosation chemistry relevant to impurity investigations. The study of N-Nitroso Perindopril therefore contributes to broader efforts to understand and evaluate nitrosamine-related impurities in pharmaceutical substances.

For pharmaceutical manufacturers, analytical laboratories, and quality control professionals, reliable impurity identification requires more than routine testing. It involves understanding molecular characteristics, investigating potential formation pathways, developing suitable analytical procedures, and using appropriate reference materials. This article explores the chemical structure, characterization considerations, and analytical significance of N-Nitroso Perindopril, including the role of impurity reference standards in pharmaceutical analysis.

1. Understanding N-Nitroso Perindopril

N-Nitroso Perindopril is a nitrosamine-related compound investigated in the context of pharmaceutical impurity profiling. Nitrosamines generally contain an N–N=O functional arrangement, in which a nitroso group is attached to a nitrogen atom. Their formation is commonly associated with reactions involving suitable amine-containing compounds and nitrosating species under particular chemical conditions.

In pharmaceutical manufacturing, the presence of nitrosamine impurities may be investigated when raw materials, process intermediates, reagents, or manufacturing conditions provide opportunities for nitrosation reactions. However, the identification of a nitrosamine-related compound does not automatically establish that it forms during the commercial manufacture or storage of a particular drug.

Understanding N-Nitroso Perindopril requires consideration of its molecular identity, the structural characteristics of its parent compound, and the analytical approaches used to distinguish it from other related substances.

2. Chemical Structure and Molecular Characteristics

Chemical structure plays a central role in understanding the behaviour of pharmaceutical impurities. Perindopril contains several functional groups, including nitrogen-containing structural features and ester functionalities. These groups contribute to its chemical properties and are relevant when evaluating possible impurity formation pathways.

The molecular characteristics listed for the N-Nitroso Perindopril reference-standard product include:

Product name: N-Nitroso Perindopril

Catalogue number: CP-P18012

CAS number: 3036581-82-2

Molecular formula: C19H31N3O6

Molecular weight: 397.47 g/mol

The molecular formula and molecular weight provide useful starting points for analytical identification. They help analysts establish expected mass characteristics and assess whether an observed analytical signal is consistent with the proposed molecular identity.

The presence of a nitroso-related structural feature is particularly relevant when evaluating the compound using mass spectrometry and other spectroscopic techniques. Nevertheless, molecular formula and molecular weight alone are not sufficient to establish structural identity. Additional evidence, including chromatographic behaviour and appropriate spectroscopic characterization, may be required.

The chemical name provided for this compound is:

(2S,3aS,7aS)-1-(N-((S)-1-Ethoxy-1-oxopentan-2-yl)-N-nitroso-L-alanyl)octahydro-1H-indole-2-carboxylic acid.

This name describes the compound's stereochemical configuration and the nitroso-containing nitrogen functionality. Maintaining stereochemical identity is important because structurally related compounds may differ in their chemical and chromatographic properties.

3. Potential Formation Pathways and Sources

Nitrosamine formation is generally associated with the reaction of susceptible amine functionalities with nitrosating agents. In pharmaceutical manufacturing, nitrite-containing raw materials, reagents, solvents, process intermediates, and certain reaction conditions may contribute to the formation of nitrosamine-related impurities.

For perindopril-related investigations, understanding the molecular structure of the parent API is an important starting point. Potential formation pathways should be evaluated through a systematic review of the manufacturing process, including:

• Raw material assessment: Investigating whether starting materials or processing aids introduce nitrite or other potential nitrosating species.

• Reaction conditions: Reviewing pH, temperature, reaction time, and other process variables that could influence nitrosation chemistry.

• Intermediate evaluation: Examining nitrogen-containing intermediates for possible interactions with nitrosating agents.

• Storage conditions: Assessing whether formulation ingredients, packaging, or storage environments could contribute to impurity formation.

These factors represent general considerations for nitrosamine risk assessment. They should not be interpreted as confirmed formation mechanisms for N-Nitroso Perindopril without supporting experimental evidence.

A documented risk assessment helps pharmaceutical manufacturers identify potential sources, determine whether targeted testing is necessary, and establish appropriate impurity control strategies.

4. Characterization of N-Nitroso Perindopril

Characterization is essential for confirming the identity and purity of pharmaceutical reference standards. For N-Nitroso Perindopril, a combination of analytical techniques can provide complementary information about its molecular structure and chemical properties.

High-Performance Liquid Chromatography (HPLC)

HPLC is widely used for separating pharmaceutical impurities from the parent active pharmaceutical ingredient and other related substances. It can help assess chromatographic purity, evaluate retention behaviour, and determine whether the compound is adequately separated from potentially interfering components.

The selection of stationary phase, mobile phase composition, pH, and detection conditions depends on the compound's physicochemical characteristics and the analytical objective.

Liquid Chromatography–Mass Spectrometry (LC-MS)

LC-MS combines chromatographic separation with mass-based detection. It is particularly useful for investigating low-level pharmaceutical impurities and confirming molecular mass characteristics.

For N-Nitroso Perindopril, mass spectrometric analysis can help assess whether the observed molecular ion is consistent with the expected molecular composition. High-resolution mass spectrometry (HRMS) may provide additional confidence through accurate-mass measurements.

Tandem Mass Spectrometry (LC-MS/MS)

LC-MS/MS offers enhanced selectivity through precursor-ion selection and monitoring of characteristic product ions. It can be useful when developing sensitive methods for the identification and quantification of nitrosamine-related impurities in complex pharmaceutical matrices.

Nuclear Magnetic Resonance (NMR) Spectroscopy

NMR spectroscopy provides information about the molecular environment of hydrogen and carbon atoms. It can support structural elucidation and help evaluate whether the proposed molecular structure is consistent with the experimental data.

Infrared (IR) Spectroscopy

IR spectroscopy identifies characteristic vibrational features associated with different functional groups. It can provide complementary structural information when used alongside chromatographic and mass spectrometric techniques.

No single analytical technique should automatically be considered sufficient for complete structural confirmation. A combination of orthogonal analytical methods, supported by appropriate reference materials and documented results, provides a stronger basis for compound identification.

5. Analytical Significance in Pharmaceutical Quality Control

The analytical significance of N-Nitroso Perindopril extends beyond its chemical identification. Pharmaceutical manufacturers must understand the presence, behaviour, and potential sources of relevant impurities to maintain appropriate quality controls.

Nitrosamine investigations generally involve several analytical objectives:

• Impurity identification: Determining whether a suspected nitrosamine-related compound is present in an API or pharmaceutical sample.

• Method development: Establishing suitable chromatographic and detection conditions for selective identification.

• Method validation: Evaluating specificity, accuracy, precision, linearity, detection capability, and quantification capability, as appropriate to the intended method.

• Impurity monitoring: Applying suitable testing strategies to assess impurity levels in relevant materials.

• Process evaluation: Using analytical findings to investigate potential sources and assess the effectiveness of corrective actions.

LC-MS/MS and high-resolution LC-MS techniques are particularly relevant to nitrosamine analysis because they can provide sensitive and selective detection.

The US Food and Drug Administration's guidance on the control of nitrosamine impurities discusses risk assessment, confirmatory testing, and appropriate control strategies for both small-molecule nitrosamines and nitrosamine drug substance-related impurities (NDSRIs). These principles provide an important framework for pharmaceutical manufacturers investigating compounds such as N-Nitroso Perindopril.

6. Importance of Reference Standards in Analytical Method Development

Reference standards play a fundamental role in pharmaceutical impurity analysis. An appropriately characterized impurity standard provides a known material against which an unknown sample can be evaluated.

For N-Nitroso Perindopril, an impurity reference standard can support several analytical activities:

• Establishing chromatographic retention characteristics.

• Supporting peak identification during HPLC and LC-MS analysis.

• Evaluating method specificity and selectivity.

• Supporting calibration and quantitative method development.

• Assessing analytical recovery and method performance.

• Comparing impurity profiles across different samples and batches.

The quality of a reference standard is important because analytical conclusions depend on the reliability of the material used for comparison. Analysts should review relevant documentation, including the certificate of analysis (COA), assigned purity, identification data, storage recommendations, and applicable handling information.

A reference standard does not replace analytical method validation. Instead, it provides a characterized material that helps laboratories develop and evaluate appropriate analytical procedures.

Parameter	N-Nitroso Perindopril	N-Nitroso Perindoprilat
Molecular formula	C19H31N3O6	C17H27N3O6
Molecular weight	397.47 g/mol	369.4 g/mol
CAS number	3036581-82-2	Not listed here
Structural distinction	Ethyl ester-containing structure	Carboxylic acid-containing structure

N-Nitroso Perindoprilat is also identified as Nitroso Perindopril EP Impurity B. Its molecular structure differs from N-Nitroso Perindopril, making accurate reference-standard selection essential during analytical investigations.

Analysts should verify the compound name, CAS number, molecular formula, molecular weight, and structural information before selecting an impurity standard or interpreting analytical results.

8. Chemicea's N-Nitroso Perindopril Reference Standard

Reliable reference materials are essential for pharmaceutical impurity characterization, analytical method development, and quality control activities. Chemicea Pharmaceuticals Pvt. Ltd. supplies pharmaceutical impurity reference standards to support the analytical requirements of pharmaceutical manufacturers, research laboratories, and quality control professionals.

Chemicea offers N-Nitroso Perindopril (CAT. No. CP-P18012) as part of its pharmaceutical impurity reference standard portfolio.

Product details include:

• Product: N-Nitroso Perindopril

• CAT. No.: CP-P18012

• CAS No.: 3036581-82-2

• Molecular Formula: C19H31N3O6

• Molecular Weight: 397.47 g/mol

For laboratories investigating perindopril-related impurities, this reference standard can support compound identification, chromatographic evaluation, and analytical method development.

Chemicea also offers custom synthesis capabilities and pharmaceutical impurity standards covering different categories of related substances, degradation products, and nitrosamine impurities. These capabilities help address specialized analytical material requirements.

N-Nitroso Perindopril is an important compound to consider in the broader investigation of nitrosamine-related pharmaceutical impurities. Understanding its molecular structure, stereochemical characteristics, potential formation pathways, and analytical behaviour helps laboratories develop appropriate strategies for impurity identification and evaluation.

Techniques such as HPLC, LC-MS, LC-MS/MS, NMR, and IR spectroscopy provide complementary information for compound characterization and analytical method development. The use of appropriately characterized reference standards further supports reliable identification, method evaluation, and pharmaceutical quality control.

For pharmaceutical manufacturers and analytical laboratories, selecting the correct impurity reference standard is an important step in maintaining accurate impurity profiling practices. Chemicea Pharmaceuticals supports these requirements through its pharmaceutical impurity reference standards and custom synthesis services, including its N-Nitroso Perindopril reference standard.

Frequently Asked Questions (FAQs)

1. What is N-Nitroso Perindopril?

N-Nitroso Perindopril is a nitrosamine-related impurity associated with perindopril. It is used as a reference material in pharmaceutical impurity identification, characterization, and analytical method development.

2. What is the molecular formula of N-Nitroso Perindopril?

Its molecular formula is C19H31N3O6, and its molecular weight is approximately 397.47 g/mol.

3. What is the CAS number of N-Nitroso Perindopril?

The CAS number of N-Nitroso Perindopril is 3036581-82-2.

4. Which analytical techniques are used to characterize N-Nitroso Perindopril?

HPLC, LC-MS, LC-MS/MS, HRMS, NMR, and IR spectroscopy can be used for complementary characterization and analytical evaluation, depending on the testing objective.

5. Why are reference standards important for N-Nitroso Perindopril analysis?

Reference standards provide characterized materials for compound identification, chromatographic comparison, calibration, and analytical method development.

6. Where can pharmaceutical laboratories source N-Nitroso Perindopril reference standards?

Pharmaceutical laboratories can source N-Nitroso Perindopril from specialized impurity reference standard suppliers such as Chemicea Pharmaceuticals. Chemicea offers this compound under catalogue number CP-P18012.